Structural Changes of Silicate Crystals under High Temperatures and High Pressures.

Structural changes in liquid Fe at high pressures and high temperatures from Synchrotron X-ray Diffraction

– High-energy synchrotron X-ray diffraction measurements on liquid iron in the vicinity of the δ-γ-liquid triple point (to 2300 K and 5 GPa) reveal significant changes in the structure of the liquid upon increasing pressure and temperature. The second and third neighbor shells in the g(r) shift to shorter distances and develop new structure with increasing pressure. The results can be interpret...

Structural stability of silica at high pressures and temperatures

The high-pressure phase diagram of SiO2 has been calculated using density-functional perturbation theory. We find that phase transitions of silica do not correspond to any observed seismic discontinuities within the Earth. We analyze the breakdown of close packing occurring in SiO2 above 200 GPa and conclude that it is due to asphericity and deformability of ions, which can generally lead to th...

Structural complexity of simple Fe2O3 at high pressures and temperatures.

Although chemically very simple, Fe2O3 is known to undergo a series of enigmatic structural, electronic and magnetic transformations at high pressures and high temperatures. So far, these transformations have neither been correctly described nor understood because of the lack of structural data. Here we report a systematic investigation of the behaviour of Fe2O3 at pressures over 100 GPa and te...

Electrical conductivity of wadsleyite at high temperatures and high pressures

degradation of oil impregnated paper insulation under influence of repetitive fast high voltage impulses

در طی سالهای اخیراستفاده ازمنابع انرژی تجدید پذیر در شبکه های مدرن بنا به دلایل زیست محیطی و اقتصادی به طور گسترده استفاده شده است همچون نیروگاههای بادی و خورشیدی .ولتاژتولیدی این نیروگاهها اغلب به فرم dc می باشد وادوات الکترونیک قدرت به عنوان مبدل و پل بین شکل موج dc وac استفاده می شوند.این پروسه باعث ایجاد پالسهایی برروی شکل موج خروجی می شود که می تواند وارد تجهیزات قدرت همچون ترانسفورماتور ی...